The wide dynamic range (WDR) or "convergent" neuron is the most populous type of those neurons whose cell bodies are located in the dorsal horn of the spinal cord. WDR neurons are responsive to all somatosensory modalities (thermal, chemical and mechanical) and a broad range of intensity of stimulation from peripheral nerves. They steadily increase their firing rate as the stimulus intensity rises into the noxious range. There are, for example, wide dynamic range neurons that respond to benign stroking as well as to painful heat and mechanical damage in the cell's receptive field.[1] Dorsal horn neurons that receive input from the viscera via thin afferent fibers are all WDR type.[2] The WDR neuron was identified by Mendell in 1966.[3]